This invention relates to expansion joints for bridging joints between pavement slabs in road bridges and elevated roads.
In order to compensate for expansion and contraction of concrete floor slabs, prestressed concrete girders, concrete girders, steel floor slabs, etc. in roads caused by changes in ambient temperature, it has been general practice to provide expansion members at the joints. For example, opposing end faces of adjacent concrete floor slabs at the joint are of such a type that as shown in FIG. 22, wavily bent vertical end face plates a, a are placed oppositely with a regular space b therebetween and thereafter concrete is deposited at the back thereof. This vertical end face plate a can be formed into an assembled joint member suitable for use at the installing site by carrying out welding of reinforcing material and preliminary assembling work at a factory or in the vicinity of the joint of a road. However, for the reasons of execution of works, transportation and standardization of size, height c of the vertical end face plate is limited to only several kinds within the range of 100-220 mm. Therefore, the thickness of a protrusion e of after-concreting enclosed with the vertical end face plate is inevitably smaller than the thickness of the floor slab and is not durable enough to stand the high load. In addition, depending upon the structure of a road, configuration of the neighbouring ground and executing conditions, the depths of opposing floor slabs at cutout portion are made larger than originally planned or are made different from each other. In these cases, the above-mentioned disadvantages become more conspicuous, involving such a defect as lack of unbalance of durability to load given by passing vehicles.
Whenever a vehicle passes over an elastic seal means of groove shape, air is sucked or sent into the groove, which generates noises. In order to prevent such noises, elastic seal or the like is usually filled in such sealing rubber. Moreover, such sealing rubber is expensive and tends to age. Also, one of the features of the above-mentioned vertical type expansion joint for roads using wavily bent end face plates is that its wavy expansion spacing at the level of the road surface involves less shock caused by slipping of vehicle tyres into the groove, as compared to the case of linear expansion spacing. It is only natural that the larger the angle of bend, the less the shock is given to a vehicle passing over it but, on the other hand, in the case of a skew bridge, such problems as limitation on the angle of bend, increased steps in the process, higher cost, etc. are raised and it is therefore required to set the angle of bend properly.